I.V. catheters are primarily used to administer fluids, sometimes containing medications, directly into a patient's vascular system. The catheter is inserted into a patient's vein by a health care worker by using a handheld placement device that includes a sharp tip needle. The needle is positioned in the interior hollow portion of the catheter with its tip extended slightly beyond the edge of the catheter. The end of the apparatus opposite the needle tip is made up of the needle connected to a needle hub which is capable of being held by the health care worker during the insertion procedure.
The insertion procedure contains four basic steps: (1) the health care worker inserts the needle and catheter together into the patient's vein; (2) after insertion into the vein with the needle point, the catheter is forwarded into the vein of the patient by the health care worker pushing the catheter with his or her finger; (3) the health care worker withdraws the needle by grasping the hub end (opposite the point end) while at the same time applying pressure to the patient's skin at the insertion site with his or her free hand; and (4) the health care worker then tapes the now inserted catheter to the patient's skin and connects the exposed end of the catheter, the catheter hub, to the source of the fluid to be administered into the patient's vein.
The problem is that immediately after the withdrawal of the needle from the patient's vein, the health care worker who is, at this time, involved in at least two urgent procedures must place the exposed needle tip at a nearby location and address the tasks required to accomplish the needle withdrawal. It is at this juncture that the exposed needle tip creates a danger of an accidental needle stick occurring, which under the circumstances, leaves the health care worker vulnerable to the transmission of various, dangerous blood-borne pathogens, including AIDS and hepatitis.
This danger to the health care worker from accidental needle sticks has caused an impetus for the development of a safer IV catheter in which the occurrence of such accidental needle sticks is prevented. Safety catheters that have been developed to achieve this result are disclosed, for example, in Lemieux Reissue Patent No. Re. 34,416, Crawford U.S. Pat. No. 5,558,651, McLees U.S. Pat. No. 5,135,504, Gaba U.S. Pat. No. 5,697,907, and Dombrowski U.S. Pat. No. 4,978,344. Kulli U.S. Pat. No. 4,929,241 and Chamuel U.S. Pat. No. 5,053,017 disclose a protective needle guard for use with a hypodermic needle.
The prior art safety catheters all exhibit one or more drawbacks that have thus far limited their usefulness and full acceptance by health-care workers. For example, in the safety catheter disclosed in the Lemieux patent, the force required to engage the needle slot within the guard flange is relatively great and would interfere with the removal of the needle. Reducing this force to a more acceptable level would create the possibility of the needle guard remaining in the catheter hub after the needle is removed from the catheter. As a result, the safety catheter disclosed in the Lemieux patent would not consistently function in a reliable manner.
Similarly, the user of the safety catheter disclosed in the Dombrowski patent would have to exert a considerable force to remove the protective cap from the catheter hub, when the cap engages a needle. The safety catheter disclosed in the Dombrowski patent would also be relatively expensive to fabricate because of its inclusion of a flexible flange and a tether.
The McLees protective device requires an irksome, extra pulling action or tug on the needle guard through a retention ring to remove the protected needle from the catheter hub. The McLees device also requires the assembly of two separate components and is thus relatively costly to manufacture. In addition, the needle in the McLees device includes a larger diameter portion near and at the needle tip. This feature of the McLees device would require that the remainder of the needle be of a lesser diameter which would have the adverse effect of slowing the blood flashback through the needle.